1. Field of the Invention
This invention relates to a tire vulcanizing press.
2. Description of the Prior Art
A tire vulcanizing press includes an upper die element and a lower die element mounted for opening and closing movement relative to each other and shapes the profile of the inner face of and vulcanizes a green tire loaded in position between the upper and lower die elements by means of an expandable and contractible elastic forming member and a heated pressurizing medium supplied into the elastic forming member.
In the case of such a tire vulcanizing press as described just above, conventionally it is the practice to place a green tire on the lower die element. According to this common practice, however, the green tire is sometimes deformed into a flattened configuration by its own weight.
An improved device for positioning a green tire accurately on a die element is disclosed in Japanese Patent Laid-Open No. 60-36111 wherein a green tire loaded in position between a pair of die elements is gripped by and held in a suspended condition on a rubber bag and, before performing shaping, while the upper and lower bead portions of the green tire are contacted with upper and lower bead rings of the die elements, pressurized fluid for inflating the green tire is supplied into the green tire to position the green tire accurately on the die elements.
The improved device disclosed in Japanese Patent Laid-Open No. 60-36111 is significant in its own way in that a green tire is held in a suspended condition. However, it involves a rubber bag provided at a central portion of an upper die element for suspending a green tire thereon.
The rubber bag is exposed to a high temperature within the die elements. Accordingly, it is a problem that the life of the rubber bag is very short.
Further, in the prior device, a filling plate for forwarding tire inflating pressurized fluid is projected below the tire suspending rubber bag. Accordingly, it is a problem that the projection forms an obstruction to shaping of a tire by means of an elastic forming member from below, which will deteriorate accuracy in shaping. It is also a problem that the durability of the elastic forming member will be deteriorated.